Observation of localized prostate cancer is often a reasonable alternative to immediate definitive treatment because many prostate cancers are non-lethal and have a protracted natural history. Active surveillance (AS) is associated with nearly 100% disease-specific survival in the management of low-risk clinically localized prostate cancer in prospective cohort studies and has been promoted in recent years as a means of stemming over-treatment of low-risk disease. However, AS seems to be an underutilized strategy in the management of prostate cancer, perhaps in part because of its association with the passive observation strategy known as watchful waiting (WW), which was more commonly recommended in elderly and infirmed men in past decades. Whereas AS seeks to identify signs of disease progression and offers definitive therapy (radiation or surgery) if progression is found WW is designed to allow prostate cancer to progress, assuming that the patient is more likely to die of other causes, and only palliative intervention is offered for symptom relief. Observation of prostate cancer has gained wider acceptance in Europe and Canada than it has in the US, where utilization remains at 10% or less among low-risk patients. In order to expand the acceptance of and adherence to AS for management of low-risk clinically localized prostate cancer, it may be necessary to distinguish it from WW in common clinical practice and to identify patient-level factors and physician communication styles that impact the decision to select AS. We propose using data from two large, community-based prospective cohort studies of men with localized prostate cancer with similar study designs (Prostate Cancer Outcomes Study [PCOS] and Comparative Effectiveness Analysis of Surgery And Radiation [CEASAR]), to compare the use of surveillance between two eras (1990s for PCOS and 2010s for CEASAR). Our aim is to determine whether the evidence demonstrating that AS is a safe alternative to active treatment has led to an increase in its use among men with low-risk disease and to increased use among younger, healthier men across the two eras (suggesting a transition from WW to AS). Secondly, we will use the CEASAR baseline questionnaire to determine the extent to which physician communication style influences the selection of AS in favor of other currently available treatments. The results of the proposed study will provide the foundation for a planned study of AS utilization within the Urological Surgery Quality Collaborative, a multi-institutional group of 7 urology practices throughout the Mid- West, Mid-Atlantic and Southeastern United States. Using an established quality assessment, quality improvement model, we aim to assess prospectively the physician and patient level barriers to AS; then perform an educational intervention with physicians in an effort to increase use of AS in appropriate clinical scenarios; then reassess to evaluate the effectiveness of the intervention. Because prostate cancer is the most commonly diagnosed cancer among men, the potential public health impact of increasing AS use is enormous.